A simulation research on thermal-pressure coupling loading of a 1:3.2 containment model

Due to the important role of nuclear power plant containment in the prevention of nuclear leaks, it is of great necessity to study the containment model’s loading mechanism and gas distribution. Most of the containment models in previous studies were of small size, with a maximum ratio of 1:4. Moreover, previous studies focused on the pressure and thermal-pressure coupling have not been examined. In this study, we take Langfang’s 1:3.2 containment model as the study object. Before the experiment, a thermal-pressure coupling simulation of the air-vapor mixed working medium was performed and the absolute pressure was loaded to 1.0 MPa. The temperature and pressure at several loading stages as well as their changes with different heights were obtained to account for stratification. The study also discovered that fluid mixing in the upper section of the containment was more intensive at the start of loading and declined with loading, accompanied by backflow and lateral movement. Pressure stratification became increasingly obvious and longitudinal temperature reverse stratification emerged as loading continued.